For the Dreamcast versions and the Japanese PlayStation 2 version, Ein has two default costumes, and over time gains three new unlockable costumes.

On the Japanese Dreamcast version, there are four ways to get each costume. Two are quick but difficult to do, while the other two take time but are easy to complete. If the player uses the UPS options, the costumes will be saved to the UPS and not the system file. This means that if the system file is copied, the costumes will not be, as the UPS is not transferable.

For the DOA2: Hardcore versions, Ein gains one more new unlockable costume, though it is exclusive to the Japanese version only.

On all versions of the game, there are four ways to get each costume. Two are quick but difficult to do, while the other two take time but are easy to complete. If the player uses the UPS options, the costumes will be saved to the UPS and not the system file. This means that if the system file is copied, the costumes will not be, as the UPS is not transferable.